JPH08164671A - Reversible thermosensible recording material and reversible thermosensible recording medium using the same - Google Patents

Abstract

PURPOSE: To improve a coloring property, a decoloring property, and image stability by using a specified fluoran compound as a leuco compound, forming a recording layer containing a color developing-subtracting agent and a binder as main components on a support, and forming a reversible thermosensible recording material. CONSTITUTION: A recording layer containing at least one kind of a fluoran compound expressed by a formula (A1 and A2 are a 1-8C alkyl group and a 2-8C alkoxyalkyl group, a heterocyclic compound in which nitrogen atoms are linked with each other, A3 is a 1-4C alkyl group, A4 and A5 are each a 1-8C alkyl group.) as a leuco compound, a color developing-subtracting agent, and a binder as main components is formed on a support to make a reversible thermosensible recording material. Practical examples of the compounds shown in the formula are 2-(2,6-dimethylanilino)-3-methyl-6-dimethylamino fluoran, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming material,
More specifically, the present invention relates to a reversible thermosensitive recording material capable of forming an image and erasing the same by controlling thermal energy, and a reversible thermosensitive recording medium using the same.

[0002]

2. Description of the Related Art In recent years, reversible heat-sensitive recording materials capable of repeatedly recording and erasing a visible image by appropriately controlling applied heat energy have been actively developed. Reversible image-forming materials are described in, for example, JP-A-Sho 5
8-191190, JP-A-60-193691, JP-A-3666525, JP-A-54-119377, JP-A-63-39377,
JP-A-63-41186, JP-A-2-18829
No. 4, or US Pat. No. 4,028,118, JP-A-50-81157, and JP-A-50-10.
There are those disclosed in JP-A-5555 and JP-A-60-264285. Among these, for example, JP-A-58
The techniques described in JP-A-191190, JP-A-60-193691, and U.S. Pat. No. 3,666,525 are provided with a recording layer composed of a color-developing agent, a color-developing agent, and a binder. Also added low vapor pressure solvents or hot melts. The color is developed by using heat energy, and the color is erased by water, water vapor, or some kind of organic solvent. These do not repeat coloring and erasing only by controlling the thermal energy applied, but the process and apparatus for erasing become complicated, and further there is a problem of record storability.

Further, Japanese Patent Laid-Open No. 54-119377,
JP-A-63-39377, JP-A-63-4118
The technology disclosed in Japanese Patent Publication No. 6 discloses a reversible thermosensitive recording material containing a resin matrix and an organic low molecular weight substance dispersed in the resin matrix as main components and a thermosensitive recording medium having a recording layer. ing. The recording method of this reversible heat-sensitive recording material does not develop or decolor by a chemical reaction,
The reverse thermosensitive recording material constituting the recording layer by controlling the thermal energy has two state transition temperatures T ₁ and T ₂ (provided that T ₁ <T ₂ ) at a temperature higher than a specific temperature T ₀ near room temperature, When heated to T ₂ or more and held and then cooled to T ₀ or less, white turbidity (light scattering due to change in crystal state of organic low molecule) occurs in the thermosensitive recording material, light scattering property increases, and maximum light blocking state is achieved. , The thermosensitive recording layer in the turbid state is T ₁
The transparency (white turbidity / transparency) is reversibly changed so that when it is heated to less than T ₂ and held, and then cooled to T ₀ or less, its light scattering property decreases (transmits light) and becomes transparent. By doing so, image formation and its erasing are performed.

Further, US Pat. No. 4,028,118,
JP-A-50-81157, JP-A-50-1055
The techniques described in JP-A-55-55 and JP-A-60-264285 show thermochromic materials, and these images only change the formed image with temperature,
There is no memory for images. However, JP-A-60-264
A certain type of thermochromic material described in Japanese Patent No. 285 is capable of maintaining an image forming state and an erasing state by keeping a recording medium in a hysteresis temperature range by utilizing a hysteresis characteristic, but it is restricted in a use environment. There is a problem in using it in the temperature environment of daily life.

Next, the present inventors have previously proposed a reversible thermosensitive recording material that chemically develops and decolors only by controlling thermal energy, and is disclosed in JP-A-2-188293 and JP-A-2- No. 188294, International publication number WO
No. 90/11898 and the like. These are a reversible heat-sensitive recording material containing a leuco compound, a color-developing / reducing agent for developing / decoloring the leuco compound by controlling heat energy, and a binder, and a reversible heat-sensitive recording material provided on a support as a heat-sensitive recording layer. It will be. This reversible thermosensitive recording material uses a compound having both a group having a color-developing effect (acidic component) and a group having a color-reducing effect (basic component) as a color-developing and color-reducing agent to control the applied heat. Coloring and erasing are performed. With this heat-sensitive recording material, it is possible to hold a stable image with time in an environment of daily life. The color developing and decoloring characteristics and the image stability are largely due to the chemical structure of the developer and decolorizer in the material.

However, the characteristics of the above reversible thermosensitive recording materials, that is, the coloring and decoloring properties or the image stability are
Not only the properties of the color-developing / reducing agent but, of course, strongly depend on the leuco compound used as the dye precursor. When a leuco compound which is generally used in a color-forming recording material such as a heat-sensitive recording material or a pressure-sensitive recording material, for example, 2- (2-chloroanilino) -6-diethylaminofluorane is used in a reversible heat-sensitive recording material, The color erasing property is good, but there are problems in color development and image stability. Also, 2
When-(2,4-dimethylalinino) -3-methyl-6-diethylaminofluorane is used, color development and image stability are good, but there is a problem in decolorization. As described above, the leuco compound generally used in the heat-sensitive recording material or the heat-sensitive recording material has advantages and disadvantages, and a leuco compound excellent in color developability and decoloring property or image stability is desired.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a reversible thermosensitive recording material containing a leuco compound, a color-developing / reducing agent that thermally reacts with the leuco compound to develop or reduce color, and a binder as a main component. It is an object of the present invention to solve the problems presented in the technology and to provide a leuco compound which is particularly excellent in all of color developing property, decoloring property and image stability.

[0008]

[Means for Solving the Problems] That is, the invention according to claim 1 is to use a leuco compound, a color-developing / reducing agent for thermally developing or reducing the color by reacting with the leuco compound, and a reversible sensation containing a binder as a main component. The thermal recording material is characterized in that the fluoran compound represented by the following general formula (1) is used alone or in combination of two or more as the leuco compound.

Embedded image (In the formula, A ₁ and A ₂ represent an alkyl group having 1 to 8 carbon atoms or an alkoxyalkyl group having 2 to 8 carbon atoms, and A ₁ and A ₂ are nitrogen atoms which are linked to each other and are bonded to each other. good .A ₃ also form a heterocyclic ring together represents an alkyl group having 1 to 4 carbon atoms, a ₄ and a ₅ are an alkyl group having 1 to 8 carbon atoms.)

Using the leuco compound represented by the above general formula (1), a reversible heat-sensitive recording medium having a reversible heat-sensitive recording material containing a color-developing / reducing agent and a binder as a main component is used for a thermal printer or the like. When the heat printing means (for example, a thermal head) of (1) is applied with heat energy (h1), for example, at a high temperature for a short time (several millimeters to hundreds of milliseconds), a color is formed and an image is formed. Further, if another heat energy (h2) is applied to this image by a heating means such as a heat roller, a heat plate, or a thermal head, for example, a heat treatment is performed at a low temperature for a long time (1 second or more), the image is erased. Erased. Further, it is possible to repeatedly form and erase an image so that an image is formed by applying heat energy (h1) to the erased recording layer in the same manner, and unless heat energy is applied, It holds the image forming state or the image erasing state.

In such image formation or image erasing, the recording layer using the leuco compound represented by the above-mentioned general formula (1) of the present invention has a high coloring density and is excellent in decoloring property and image stability. This was difficult to predict from the conventional thermal paper technology used in the past.

Next, each material constituting the reversible thermosensitive recording material of the present invention will be described. Examples of the leuco compound represented by the above chemical formula (1) according to the present invention are shown below, but the present invention is not limited thereto. As a specific example, 2- (2,6-dimethylanilino) -3-
Methyl-6-dimethylaminofluorane, 2- (2,6
-Dimethylanilino) -3-methyl-6-diethylaminofluorane, 2- (2,6-dimethylanilino) -3
-Methyl-6- (N-methyl-N-ethylamino) fluorane, 2- (2,6-dimethylanilino) -3-methyl-6-di-n-propylaminofluorane, 2-
(2,6-Dimethylanilino) -3-methyl-6- (N
-Methyl-Nn-propylamino) fluorane, 2-
(2,6-Dimethylanilino) -3-methyl-6-diisopropylaminofluorane, 2- (2,6-dimethylanilino) -3-methyl-6-di-n-butylaminofluorane, 2- (2,6-Dimethylanilino) -3-methyl-6- (N-methyl-Nn-butylamino) fluorane, 2- (2,6-dimethylanilino) -3-methyl-6-diisobutylamino Fluoran, 2- (2,6
-Dimethylanilino) -3-methyl-6- (N-methyl-N-isobutylamino) fluorane, 2- (2,6-
Dimethylanilino) -3-methyl-6- (N-ethyl-
N-isobutylamino) fluorane, 2- (2,6-dimethylanilino) -3-methyl-6- (N-ethyl-N
-Sec-butylamino) fluorane, 2- (2,6-
Dimethylanilino) -3-methyl-6-di-n-pentylaminofluorane, 2- (2,6-dimethylanilino) -3-methyl-6-diisopentylaminofluorane, 2- (2,2 6-dimethylanilino) -3-methyl-
6- (N-ethyl-N-isopentylamino) fluorane, 2- (2,6-dimethylanilino) -3-methyl-
6-di-n-hexylaminofluorane, 2- (2,6
-Dimethylanilino) -3-methyl-6- (Nn-butyl-N-isohexylamino) fluorane, 2-
(2,6-Dimethylanilino) -3-methyl-6-di-
n-heptylaminofluorane, 2- (2,6-dimethylanilino) -3-methyl-6-di-n-octylaminofluorane, 2- (2,6-dimethylanilino) -3
-Methyl-6- (N-methyl-N-n-octylamino) fluorane, 2- (2,6-dimethylanilino)-
3-Methyl-6- [N-ethyl-N- (2-ethylhexyl) amino] fluorane, 2- (2,6-dimethylanilino) -3-methyl-6- [N-methyl-N- (2-
Methoxyethyl) amino] fluorane, 2- (2,6-
Dimethylanilino) -3-methyl-6- [N-methyl-
N- (2-ethoxyethyl) amino] fluorane, 2-
(2,6-Dimethylanilino) -3-methyl-6- [N
-Methyl-N- (3-ethoxypropyl) amino] fluorane, 2- (2,6-dimethylanilino) -3-methyl-6- [N-ethyl-N- (2-methoxyethyl) amino] fluorane, 2- (2,6-dimethylanilino)
-3-Methyl-6- [N-ethyl-N- (2-ethoxyethyl) amino] fluorane, 2- (2,6-dimethylanilino) -3-methyl-6- [N-ethyl-N- ( Three
-Ethoxypropyl) amino] fluorane, 2- (2,
6-Dimethylanilino) -3-methyl-6- [N-ethyl-N- (3-methoxypropyl) amino] fluorane, 2- (2,6-dimethylanilino) -3-methyl-
6- [N-ethyl-N- (4-methoxybutyl) amino] fluorane, 2- (2,6-dimethylanilino)-
3-Methyl-6- [N-ethyl-N- (4-ethoxybutyl) amino] fluorane, 2- (2,6-dimethylanilino) -3-methyl-6-bis (2-methoxyethyl) aminoflu Oran, 2- (2,6-dimethylanilino) -3-methyl-6-bis (2-ethoxyethyl) aminofluorane, 2- (2,6-dimethylanilino)-
3-Methyl-6-bis (3-ethoxypropyl) aminofluorane, 2- (2,6-dimethylanilino) -3-
Methyl-6-pyrrolidinofluorane, 2- (2,6-dimethylanilino) -3-methyl-6-piperidinofluorane, 2- (2,6-dimethylanilino) -3-ethyl-6 -Diethylaminofluorane, 2- (2,6-dimethylanilino) -3-ethyl-6-di-n-butylaminofluorane, 2- (2,6-dimethylanilino) -3
-Ethyl-6- (N-methyl-N-isobutylamino)
Fluoran, 2- (2,6-dimethylanilino) -3-
Ethyl-6-di-n-pentylaminofluorane, 2-
(2,6-Dimethylanilino) -3-ethyl-6-di-
n-octylaminofluorane, 2- (2,6-dimethylanilino) -3-ethyl-6- [N-ethyl-N-
(2-Methoxyethyl) amino] fluorane, 2-
(2,6-Dimethylanilino) -3-ethyl-6-piperidinofluorane, 2- (2,6-dimethylanilino)
-3-n-Propyl-6- (N-ethyl-N-n-octylamino) fluorane, 2- (2,6-diethylanilino) -3-n-butyl-6-diethylaminofluorane, 2- ( 2,6-diethylanilino) -3-ethyl-
6-Dimethylaminofluorane, 2- (2,6-diethylanilino) -3-ethyl-6-diethylaminofluorane, 2- (2,6-diethylanilino) -3-methyl-6-di-n -Propylaminofluorane, 2- (2,
6-Diethylanilino) -3-methyl-6- (N-methyl-Nn-propylamino) fluorane, 2- (2,2
6-diethylanilino) -3-methyl-6-diisopropylaminofluorane, 2- (2,6-diethylanilino) -3-methyl-6-di-n-butylaminofluorane, 2- (2,2 6-diethylanilino) -3-methyl-
6- (N-methyl-N-isobutylamino) fluorane, 2- (2,6-diethylanilino) -3-methyl-
6-di-n-pentylaminofluorane, 2- (2,6
-Diethylanilino) -3-methyl-6-di-n-hexylaminofluorane, 2- (2,6-diethylanilino) -3-methyl-6-di-n-octylaminofluorane, 2- (2,6-Diethylanilino) -3-methyl-6- [N-ethyl-N- (2-methoxyethyl) amino] fluorane, 2- (2,6-diethylanilino)-
3-Methyl-6- [N-ethyl-N- (2-ethoxyethyl) amino] fluorane, 2- (2,6-diethylanilino) -3-methyl-6-bis (3-ethoxypropyl) aminoflu Oran, 2- (2,6-diethylanilino) -3-methyl-6-pyrrolidinofluorane, 2-
(2,6-Diethylanilino) -3-methyl-6-piperidinofluorane, 2- (2,6-diethylanilino)
-3-Ethyl-6-diethylaminofluorane, 2-
(2,6-Diethylanilino) -3-ethyl-6-di-
n-Butylaminofluorane, 2- (2,6-diethylanilino) -3-ethyl-6- (N-ethyl-N-isobutylamino) fluorane, 2- (2,6-diethylanilino) -3 -Ethyl-6-di-n-pentylaminofluorane, 2- (2,6-diethylanilino) -3-ethyl-6-di-n-octylaminofluorane, 2-
(2,6-Diethylanilino) -3-ethyl-6- [N
-Ethyl-N- (2-methoxyethyl) amino] fluorane, 2- (2,6-diethylanilino) -3-ethyl-6-piperidinofluorane, 2- (2-methyl-6-
Ethylanilino) -3-methyl-6-diethylaminofluorane, 2- (2-methyl-6-ethylanilino)-
3-methyl-6-di-n-butylaminofluorane, 2
-(2-Methyl-6-ethylanilino) -3-methyl-
6-di-n-octylaminofluorane, 2- (2-methyl-6-ethylanilino) -3-methyl-6- [N-
Ethyl-N- (2-methoxyethyl) amino] fluorane, 2- (2-methyl-6-ethylanilino) -3-methyl-6-piperidinofluorane, 2- (2-methyl-
6-ethylanilino) -3-ethyl-6- (Nn-butyl-N-sec-butylamino) fluorane, 2-
(2-Methyl-6-ethylanilino) -3-ethyl-6
-Diisooctylaminofluorane, 2- (2-methyl-6-ethylanilino) -3-ethyl-6- [N-ethyl-N- (4-ethoxybutyl) amino] fluorane,
2- (2-Methyl-6-ethylanilino) -3-ethyl-6-pyrrolidinofluorane, 2- (2,6-di-n-
Propylanilino) -3-methyl-6-diethylaminofluorane, 2- (2,6-di-n-propylanilino) -3-methyl-6-di-n-propylaminofluorane, 2- (2 , 6-Di-n-propylanilino) -3
-Methyl-6- (N-ethyl-N-isobutylamino)
Fluoran, 2- (2,6-di-n-propylanilino) -3-methyl-6-di-n-octylaminofluorane, 2- (2,6-di-n-propylanilino) -3
-Methyl-6- [N-ethyl-N- (2-methoxyethyl) amino] fluorane, 2- (2,6-di-n-propylanilino) -3-methyl-6-bis (3-methoxypropyl) ) Aminofluorane, 2- (2,6-di-n-
Propylanilino) -3-methyl-6-piperidinofluorane, 2- (2,6-di-n-propylanilino)-
3-ethyl-6-diethylaminofluorane, 2-
(2,6-di-n-propylanilino) -3-ethyl-
6-di-n-butylaminofluorane, 2- (2,6-
Di-n-propylanilino) -3-ethyl-6- [N-
n-Butyl-N- (2-methoxyethyl) amino] fluorane, 2- (2,6-di-n-propylanilino)-
3-ethyl-6-piperidinofluorane, 2- (2,6
-Diisopropylanilino) -3-methyl-6-dimethylaminofluorane, 2- (2,6-diisopropylanilino) -3-methyl-6-diethylaminofluorane, 2- (2,6-diisopropylanilino) -3-Methyl-6-di-n-propylaminofluorane, 2-
(2,6-diisopropylanilino) -3-methyl-6
-Diisopropylaminofluorane, 2- (2,6-diisopropylanilino) -3-methyl-6-di-n-butylaminofluorane, 2- (2,6-diisopropylanilino) -3-methyl-6 -(N-methyl-N-n-
Butylamino) fluorane, 2- (2,6-diisopropylanilino) -3-methyl-6-di-n-pentylaminofluorane, 2- (2,6-diisopropylanilino) -3-methyl-6- Di-n-octylaminofluorane, 2- (2,6-diisopropylanilino) -3-
Methyl-6- [N-ethyl-N- (3-ethoxypropyl) amino] fluorane, 2- (2,6-diisopropylanilino) -3-methyl-6-bis (4-methoxybutyl) aminofluorane, 2- (2,6-diisopropylanilino) -3-methyl-6-pyrrolidinofluorane, 2- (2,6-diisopropylanilino) -3-methyl-6-piperidinofluorane, 2- ( 2,6-Diisopropylanilino) -3-ethyl-6-diethylaminofluorane, 2- (2,6-diisopropylanilino) -3-ethyl-6-di-n-butylaminofluorane, 2- (2 , 6-Diisopropylanilino) -3-ethyl-6-di-n-octylaminofluorane, 2-
(2,6-Diisopropylanilino) -3-ethyl-6
-Piperidinofluorane, 2- (2-ethyl-6-isopropylanilino) -3-methyl-6-diethylaminofluorane, 2- (2-methyl-6-isopropylanilino) -3-methyl-6 -Di-n-butylaminofluorane, 2- (2-ethyl-6-n-propylanilino)
-3-Methyl-6-di-n-pentylaminofluorane, 2- (2-isopropyl-6-n-propylanilino) -3-methyl-6-di-n-octylaminofluorane, 2- ( 2-ethyl-6-n-propylanilino)
-3-Methyl-6- [Nn-butyl-N- (2-methoxyethyl) amino] fluorane, 2- (2-methyl-
6-isopropylanilino) -3-methyl-6-piperidinofluorane, 2- (2-methyl-6-n-propylanilino) -3-ethyl-6-diethylaminofluorane, 2- (2,2 6-di-n-butylanilino) -3-methyl-6-dimethylaminofluorane, 2- (2,6-
Di-n-butylanilino) -3-methyl-6-diethylaminofluorane, 2- (2,6-diisobutylanilino) -3-methyl-6-di-n-butylaminofluorane, 2- (2-methyl -6-n-Butylanilino) -3
-Methyl-6-diisopropylaminofluorane, 2-
(2,6-di-n-butylanilino) -3-methyl-6
-(N-ethyl-N-isobutylamino) fluorane,
2- (2,6-di-n-butylanilino) -3-methyl-6-di-n-pentylaminofluorane, 2- (2,2
6-di-sec-butylanilinino) -3-methyl-6
-Di-n-octylaminofluorane, 2- (2-n-
Propyl-6-n-butylanilino) -3-methyl-6
-(N-ethyl-N-2-methoxyethylamino) fluorane, 2- (2-n-propyl-6-isobutylanilino) -3-methyl-6-bis (3-methoxypropyl) aminofluorane, 2 -(2,6-di-n-butylanilino) -3-methyl-6-pyrrolidinofluorane,
2- (2,6-di-n-butylanilino) -3-methyl-6-piperidinofluorane, 2- (2-isopropyl-6-isobutylanilino) -3-ethyl-6-diethylaminofluorane, 2- (2,6-diisobutylanilino) -3-ethyl-6-di-n-butylaminofluorane, 2- (2,6-di-n-butylanilino) -3-
Ethyl-6-piperidinofluorane, 2- (2,6-di-n-pentylanilino) -3-methyl-6-diethylaminofluorane, 2- (2,6-diisopentylanilino)- 3-methyl-6-di-n-propylaminofluorane, 2- (2-methyl-6-n-pentylanilino) -3-methyl-6-diisopropylaminofluorane, 2- (2-ethyl-6) -Isopentylanilino)-
3-methyl-6- (N-ethyl-N-isobutylamino) fluorane, 2- (2,6-di-n-pentylanilino) -3-methyl-6-di-n-pentylaminofluorane, 2 -(2-n-Propyl-6-isopentylanilino) -3-methyl-6-di-n-octylaminofluorane, 2- (2-ethyl-6-neopentylanilino) -3-methyl- 6- [N-methyl-N- (2-ethoxyethyl) amino] fluorane, 2- (2-n-butyl-6-isopentylanilino) -3-methyl-6-bis (4-methoxybutyl) amino Fluoran, 2-
(2,6-di-n-butylanilino) -3-methyl-6
-Pyrrolidinofluorane, 2- (2,6-di-n-pentylanilino) -3-methyl-6-piperidinofluorane, 2- (2-isobutyl-6-n-pentylanilino)- 3-ethyl-6-diethylaminofluorane, 2
-(2,6-di-sec-pentylanilino) -3-ethyl-6-di-n-butylaminofluorane, 2-
(2,6-di-n-pentylanilino) -3-ethyl-
6-di-n-octylaminofluorane, 2- (2-ethyl-6-neopentylanilino) -3-ethyl-6-
Pyrrolidinofluorane, 2- (2,6-di-n-hexylanilino) -3-methyl-6-diethylaminofluorane, 2- (2-methyl-6-n-hexylanilino)
-3-methyl-6-di-n-butylaminofluorane,
2- (2-Ethyl-6-isohexylanilino) -3-
Methyl-6- (N-ethyl-N-n-butylamino) fluorane, 2- (2-n-butyl-6-n-hexylanilino) -3-methyl-6-di-n-pentylaminofluorane , 2- (2-n-propyl-6-sec-hexylanilino) -3-methyl-6-di-n-octylaminofluorane, 2- (2,6-isohexylanilino) -3-methyl -6- [N-n-butyl-N- (3-
Ethoxybutyl) amino] fluorane, 2- (2,6-
Di-n-hexylanilino) -3-methyl-6-pyrrolidinofluorane, 2- (2,6-di-n-hexylanilino) -3-methyl-6-piperidinofluorane, 2-
(2-n-pentyl-6-n-hexylanilino) -3
-Ethyl-6-di-n-butylaminofluorane, 2-
(2,6-di-n-hexylanilino) -3-ethyl-
6-di-n-octylaminofluorane, 2- (2,6
-Di-n-heptylanilino) -3-methyl-6-diethylaminofluorane, 2- (2-ethyl-6-n-heptylanilino) -3-methyl-6-di-n-butylaminofluorane, 2- ( 2,6-di-sec-heptylanilino) -3-methyl-6-di-n-octylaminofluorane, 2- (2,6-isoheptylanilino)-
3-Methyl-6- [Nn-octyl-N- (2-methoxyethyl) amino] fluorane, 2- (2,6-di-
n-heptylanilino) -3-methyl-6-piperidinofluorane, 2- (2,6-di-n-octylanilino) -3-methyl-6-dimethylaminofluorane, 2
-(2,6-di-n-octylanilino) -3-methyl-6-diethylaminofluorane, 2- (2-ethyl-
6-n-octylanilino) -3-methyl-6-di-n
-Butylaminofluorane, 2- [2-methyl-6-
(2-Ethylhexyl) anilino] -3-methyl-6-
(N-ethyl-N-isopentylamino) fluorane,
2- (2-n-butyl-6-n-octylanilino)-
3-methyl-6-di-n-pentylaminofluorane,
2- (2,6-di-n-octylanilino) -3-methyl-6-di-n-octylaminofluorane, 2-
(2,6-isooctylanilino) -3-methyl-6-
[N-ethyl-N- (2-methoxyethyl) amino] fluorane, 2- (2,6-di-n-octylanilino)
-3-Methyl-6-pyrrolidinofluorane, 2- (2-
n-Pentyl-6-n-octylanilino) -3-methyl-6-piperidinofluorane, 2- (2,6-di-n
-Octylanilino) -3-ethyl-6-di-n-butylaminofluorane and the like. The above leuco compounds may be used alone or in combination of two or more.

Further, the developer / color-reducing agent used in the present invention is preferably a compound having both properties of an acidic component and a basic component. By controlling the thermal energy in the presence of the leuco compound shown in the above specific examples. Any image forming and erasing image may be used. Further, from the viewpoint of color developability, decoloring property and image stability, a compound having both an acidic component consisting of a phenolic hydroxyl group or a carboxyl group and a basic group consisting of an amino group, which is acidic due to a difference in thermal energy Alternatively, it becomes basic and causes the leuco compound to develop (develop) and reduce (decolor). The basic group may be present as a functional group or may be present as part of the salt. Examples of the developer / color-reducing agent having an amino group as a functional group include aminobenzoic acid, hydroxyaminobenzoic acid, aminophenols, aminonaphthoic acids, and the like. As specific examples, p-aminobenzoic acid, m-aminobenzoic acid, o-aminobenzoic acid, 4-
Amino-3-methylbenzoic acid, 3-amino-4-methylbenzoic acid, 2-amino-5-ethylbenzoic acid, 3-amino-4-butylbenzoic acid, 4-amino-3-methoxybenzoic acid, 3- Amino-4-ethoxybenzoic acid, 2-amino-5-chlorobenzoic acid, 4-amino-3-bromobenzoic acid, 2-amino-4-nitrobenzoic acid, 4-amino-
There are 3-nitrobenzoic acid, 3-amino-4-nitrilebenzoic acid, aminosalicylic acid, diaminobenzoic acid, 2-methyl-5-aminonaphthoic acid, 3-ethyl-4-aminonaphthoic acid and the like.

The compound having a basic group as a part of the salt is a salt or complex salt of a compound having a phenolic hydroxyl group or a carboxyl group and a compound having an amino group, such as hydroxybenzoic acids and hydroxysalicylic acids. Examples thereof include salts or complex salts of acids such as gallic acids and bisphenolacetic acid with aliphatic amines, phenylalkylamines and trialkylamines. As a specific example, p-hydroxybenzoic acid-alkylamine salt, p
-Hydroxybenzoic acid-phenylalkylamine salt, m
-Hydroxybenzoic acid-alkylamine salt, 2,4-dihydroxybenzoic acid-alkylamine salt, 4,5-dihydroxybenzoic acid-tolylalkylamine salt, p-hydroxybenzoic acid methyl-alkylamine salt, p-hydroxybenzoic acid Stearyl-alkylamine salts, gallic acid-alkylamine salts, gallic acid dodecyl-alkylamine salts, gallic acid stearyl-alkylamine salts, bisphenolacetic acid-alkylamine salts, bisphenolacetic acid stearyl-alkylamine salts, bisphenolacetic acid octyl-alkylamine Salt etc. are mentioned.

Further, these color-developing / reducing agents are disclosed in Japanese Patent Application Laid-Open No. 2-188293 and Japanese Patent Application Laid-Open No. 2-188293 filed by the present inventors.
No. 188294, International Publication Number WO90 / 118
Materials described in No. 98 and the like can also be mentioned. Also, two or more kinds may be used at the same time.

As the binder used in the present invention, a generally used polymer resin which is soluble in water or an organic solvent can be used. Specific examples of such polymer resins include polyvinyl alcohol, methyl cellulose, cellulose acetate, methoxy cellulose,
Carboxymethyl cellulose, hydroxyethyl cellulose, polyvinylpyrrolidone, gelatin, casein, starches, water-soluble polymers such as sodium polyacrylate, styrene-maleic acid copolymer, polystyrene, polyvinyl chloride, linear saturated polyester, polymethacrylic acid Homo or copolymer of methacrylic resin such as methyl or polyethyl methacrylate, polyurethane, polybutyral, nitrocellulose, ethyl cellulose, epoxy resin, acrylic resin, polyester, paraffin wax, polyethylene wax, carnauba wax, microcrystalline wax, Solvent-soluble polymers such as stearic acid amide and rubbers can be used.

The content of each component of the recording layer composition of the reversible thermosensitive recording material of the present invention is not particularly limited, but it is 0.1 to 2 parts by weight of the leuco compound to 1 part by weight of the color-developing and reducing agent. Further, the binder is preferably 2 parts by weight or less.

Next, a specific method for producing the reversible thermosensitive recording material of the present invention will be described, but the invention is not limited thereto. As a specific example of the method for producing the reversible thermosensitive recording material of the present invention, any aspect may be used as long as it contains the above leuco compound, a color-developing and reducing agent and a binder.
A binder is dissolved in a coating liquid composed of a leuco compound which is uniformly dispersed or dissolved in water or an organic solvent, and a color-developing agent. The invention according to claim 2 relates to the invention of a reversible thermosensitive recording medium using a coating liquid comprising the reversible thermosensitive recording material in a recording layer.

That is, the invention according to claim 2 is a reversible thermosensitive recording medium comprising a support and a recording layer containing the reversible thermosensitive recording material according to claim 1.

The invention according to claim 3 is the invention according to claim 2
Of the reversible thermosensitive recording medium of the present invention.

That is, the invention according to claim 3 is based on the reversible thermosensitive recording medium according to claim 2, and is characterized in that a protective layer is provided on the recording layer.

As shown in FIG. 1, the reversible thermosensitive recording medium 1 according to the present invention comprises a recording layer coating liquid comprising the above coating liquid, paper, synthetic paper, plastic film or sheet such as polyester, PS or PP. , Bar coating, blade coating on support 2 such as paper laminated with synthetic resin,
The recording layer 3 is provided by coating and drying by a coating method such as air knife coating, gravure coating or roll coating. At this time, the coating amount of the recording layer 3 after drying is 3
-10 g / m ² is suitable.

The leuco compound and the color-developing / reducing agent may be present in the recording layer 3 in the form of microcapsules. As the microencapsulation method at this time, various known methods are used, for example, an interfacial polymerization method,
The in situ polymerization method, the coacervation method, the spray drying method, the in-liquid drying method and the like can be mentioned.

Further, on the recording layer comprising a leuco compound, a color-reducing agent and a binder on the support 2, the thermal head matching property (adhesion of dust to the thermal head, sticking) is improved, or the durability of the recording layer 3 is imparted. Providing the protective layer 4 for the purpose does not impair the characteristics of the recording material of the present invention. For example, as a protective layer component, an inorganic filler such as talc, calcium carbonate, titanium oxide, and silicon oxide, an organic filler such as Teflon resin, a silicone resin, and a urea-formalin resin, a lubricant such as waxes, and a high-level filler used for the recording layer binder are used. A combination of a molecular resin, a thermosetting resin, an electron beam curable resin, a silicone resin, or the like is used.

Further, in the recording layer made of the reversible thermosensitive recording material according to the present invention, in addition to the above leuco compound, the color-developing / reducing agent and the binder, additives which are applied to ordinary thermosensitive recording paper may be added. Good. Specific examples thereof include dispersants such as surfactants, color image stabilizers, antioxidants, light stabilizers, and inorganic or organic pigments. Further, a melting point depressant for adjusting the color developing sensitivity and the decoloring temperature of the recording layer may be contained. As a specific example, stearic acid amide,
Examples include higher fatty acid amides such as palmitic acid amide, benzenesulfonic acid amides, benzyloxynaphthalene, and benzylbiphenyl. Although not shown, an undercoat layer may be provided between the recording layer 3 and the support 2, and a backcoat layer may be provided on the surface opposite to the surface on which the recording layer 3 is formed, if necessary.

The principle of image formation and deletion by the reversible thermosensitive recording material of the present invention is as follows. That is, when an acidic substance comes into contact with the leuco compound, which is a basic dye, the lactone ring in the leuco compound is opened to form a coloring system. On the contrary, when a basic substance comes into contact with a dye that is a coloring system, the lactone ring is closed and the original colorless leuco body is restored. This coloring and decoloring phenomenon can be controlled by, for example, using a compound having both a group having a color developing effect (acid component) and a group having a color reducing effect (basic component) as a color developing and reducing agent. Achieved by

The color-developing and decoloring agent in the color-developing / decoloring mechanism of the system here is itself alkaline. However, the reaction rate at which the acidic component opens the lactone ring of the leuco compound is
Faster than the reaction rate of the basic component closing the ring. Therefore, the chromophore is melted by heating and the lactone ring is preferentially cleaved by the acidic component (for example, a hydrogen ion is released from the phenolic hydroxyl group or the carboxyl group of the chromophore and reacts with the leuco compound to give a leuco compound. Is open). Next, ring closure occurs due to the basic component, but the heat is rapidly spread and rapidly cooled due to high-speed point heating of the thermal head or the like, so that it is fixed in a colored state. In the case of gradual cooling, it is considered that after the ring is once opened, the basic component closes the ring and tilts to decolorize the leuco body (for example, hydrogen ions are deprived by the action of the amino group of the color-developing / reducing agent and leuco compound is removed). The compound is closed). That is, the color develops when heated and rapidly cooled with a thermal head, and the color disappears when heated and gradually cooled with a thermal stamp. Coloring and decoloring occur reversibly and can be repeated. The thermal head at the time of color development can be regarded as heating and rapid cooling, and the thermal stamp at the time of color erasing can be regarded as heating and gradual cooling. Those states are maintained in the environment of daily life. As described above, the coloring and decoloring properties are not only largely due to the chemical structure of the developer and decolorizer used, but also due to the reversibility of the leuco compound. By using the leuco compound represented by the general formula (1) of the present invention, it is possible to improve the properties of the recording material, especially the color developability, the color erasability and the storability of the recorded image.

Further, a method of recording on the recording layer of the reversible thermosensitive recording medium of the present invention will be described. To form an image, it is only necessary to control the heat energy of heating / quenching, and for example, it is possible to use a heating printing means such as a thermal head or a semiconductor laser. On the other hand, in the case of image erasing, it suffices if the heat energy of heating / slow cooling can be controlled.
It becomes possible by using radiant heat from a heat roll, a thermal head, or the like.

[0028]

According to the present invention, the leuco compound has the general formula (1)
The reversible heat-sensitive recording material containing at least a fluoran compound, a color-developing / reducing agent having both an acidic component having a color-developing effect and a basic component having a color-reducing effect, and a binder has a basic property by controlling thermal energy. When the acidic component of the color-developing agent contacts the leuco compound, which is a dye, the lactone ring in the leuco compound opens and develops the color, and when the basic component of the color-reducing agent contacts the colored leuco compound, the lactone ring closes.・ Returns to the decolorized leuco body.

Further, since the reversible thermosensitive recording medium of the present invention is composed of the above reversible thermosensitive recording material, it exhibits excellent recording properties in the recording layer, such as color developability and decoloring property, and the recorded image has excellent storability. improves.

[0030]

EXAMPLES Examples of the present invention will be described in detail below. In addition, "part" in an Example has shown the weight part.

<Example 1> (A) Preparation of reversible thermosensitive recording material

Embedded image The above fluoran compound (leuco compound) 20 parts Salt of gallic acid and stearylamine (developing / reducing agent) 60 parts Polyvinyl alcohol 30 parts Stearic acid amide 30 parts Water / isopropyl alcohol (7/3) 1000 parts Mix the above composition well After that, it was pulverized and dispersed with a paint conditioner to obtain a recording layer coating liquid. (B) Preparation of reversible thermosensitive recording medium The coating liquid prepared in (A) was applied to a 100 μm white polyethylene terephthalate (PET) sheet using a Meyer bar to form a recording layer so that the coating thickness after drying would be 6 μm. did. A reversible thermosensitive recording medium is prepared by applying a protective coating liquid containing an ultraviolet curable resin as a main component on this recording layer using a Meyer bar and further curing it by irradiating with ultraviolet rays to form a protective layer having a film thickness of 1.5 μm. did.

Example 2 Example 1 was repeated except that 20 parts of the leuco compound represented by the following chemical formula (3) was used instead of 20 parts of the leuco compound represented by the chemical formula (2) used in Example 1. A reversible thermosensitive recording material was prepared in the same manner as in 1. to prepare a reversible thermosensitive recording medium.

[Chemical 4]

Example 3 Example 1 was repeated except that 20 parts of the leuco compound represented by the chemical formula (2) used in Example 1 was replaced with 20 parts of the leuco compound represented by the following chemical formula (4). A reversible thermosensitive recording material was prepared in the same manner as in 1. to prepare a reversible thermosensitive recording medium.

Embedded image

Example 4 Example 1 was repeated except that 20 parts of the leuco compound represented by the chemical formula (2) used in Example 1 was replaced with 20 parts of the leuco compound represented by the following chemical formula (5). A reversible thermosensitive recording material was prepared in the same manner as in 1. to prepare a reversible thermosensitive recording medium.

[Chemical 6]

Example 5 Example 1 was repeated except that 20 parts of the leuco compound represented by the chemical formula (2) used in Example 1 was replaced with 20 parts of the leuco compound represented by the following chemical formula (6). A reversible thermosensitive recording material was prepared in the same manner as in 1. to prepare a reversible thermosensitive recording material.

[Chemical 7]

Comparative Example 1 The procedure was carried out except that 20 parts of 2- (2-chloroanilino) -6-diethylaminofluorane was used instead of 20 parts of the leuco compound represented by the chemical formula (2) used in Example 1. A reversible thermosensitive recording material was prepared in the same manner as in Example 1 to prepare a reversible thermosensitive recording material.

Comparative Example 2 In place of 20 parts of the leuco compound represented by the chemical formula (2) used in Example 1, 2-
A reversible thermosensitive recording material was prepared in the same manner as in Example 1 except that 20 parts of (2,4-dimethylanilino) -3-methyl-6-diethylaminofluorane was used.

[Confirmation Test] Next, the reversible thermosensitive recording media of Examples 1 to 5 and the reversible thermosensitive recording media of Comparative Examples 1 and 2 were measured using a thermal printer (thermal head: 8 dot / mm). 0.35 mJ / dot
In addition to printing under the printing energy condition of No. 1, each printed recording medium was pressed by a hot stamp plate heated to 110 ° C. for 1 second to erase, and these printing / erasing operations were repeated. Table 1 below shows each data of the background density, the erasing rate, the color density and the print storability obtained in the printing / erasing operation for each recording medium.

[0039]

[Table 1]

Each density in the table is a value obtained by measuring the optical reflection density with a Macbeth reflection densitometer. The erasure rate is a value obtained by dividing the value obtained by subtracting the background density from the erase density by the value obtained by subtracting the background density from the color development density. Further, the print storability is a density residual ratio after leaving for 72 hours at 30 ° C. after printing.

Examples 1 to 5 and Comparative Examples 1 and 2 in Table 1
In comparison with Comparative Examples 1-2, Examples 1-5 have
It was confirmed that it exhibited the characteristics of having all of color developability, erasability and print storability.

[0042]

As shown in Table 1, the above general formula (1)
By the reversible thermosensitive recording material consisting of a leuco compound represented by and a leuco compound that reversibly changes the color development by controlling the thermal energy, and a reversible thermosensitive recording material composed of a binder, excellent recording properties of color development and decolorization can be obtained. It is possible to obtain a reversible thermosensitive recording material which has the excellent image storage stability and which does not deteriorate the recorded image under the environment of daily life.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a reversible thermosensitive recording medium of the present invention. 1 Reversible Thermosensitive Recording Medium 2 Support 3 Recording Layer 4 Protective Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yojiro Kumagai 1-43 Minami, Yugemachi, Yao-shi, Osaka Yamamoto Kasei Co., Ltd.

Claims (3)

[Claims] 1. A reversible thermosensitive recording material comprising, as a main component, a leuco compound, a color-developing / reducing agent that thermally reacts with the leuco compound to develop or reduce color, and the leuco compound has the following general formula: A reversible thermosensitive recording material comprising a fluoran compound represented by 1) alone or in combination of two or more kinds. Embedded image (In the formula, A ₁ and A ₂ represent an alkyl group having 1 to 8 carbon atoms or an alkoxyalkyl group having 2 to 8 carbon atoms, and A ₁ and A ₂ are nitrogen atoms which are linked to each other and are bonded to each other. good .A ₃ also form a heterocyclic ring together represents an alkyl group having 1 to 4 carbon atoms, a ₄ and a ₅ are an alkyl group having 1 to 8 carbon atoms.) 2. A reversible thermosensitive recording medium comprising a support and a recording layer containing the reversible thermosensitive recording material according to claim 1. 3. The reversible thermosensitive recording medium according to claim 2, wherein a protective layer is provided on the recording layer.